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2nd Start ( Kinda long, But I need HELP)

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Discussion starter · #21 · (Edited)
Just to update my problem, I've replaced the cold start switch and IAC sensor this weekend. Same problem. I have no clue where to go from here. I've got a MAF sensor coming (EBay special) and then I'm gonna change the o2 sensor. That will be all sensors in the fuel system. Any other suggestions greatly appreciated. By the way, both cold start switches ohmed the same cold.
Thanks for everyones help, please keep troubleshooting tips coming as this is really beginning to get expensive, not to mention how its PISSING me off.
Thanks again,
Jerry
 
#22 ·
Cold start switches or sensors? Cold start switch, I don't think you have one since the eng has a MAF, would be under the thermostat housing. ECM Coolant temp sensor is either to the side of the thermostat or on pass side head, between 6 & 8 cylinder.

Take your extra sensor and freeze it for about 15-20 minutes, then plug it into the coolant sensor connector going to the ECM. Hold throttle open about half and start the engine.
 
Discussion starter · #23 ·
Local dealership and the invoice calls it a "cold start switch", although I agree with you, it looks like a sensor. Actually it looks like a large temp bulb. But whatever it is called, it is located in the lower intake on the pax side of center, next to the coolant temp sensor. Good idea about freezing the old sensor. I'll try to give that a try tomorrow.
Thanks,
Jerry
 
Discussion starter · #25 ·
Well Folks,
I still have my start problem. Since my last post I've replaced the O2 sensor, the MAF sensor, had the computer chip reprogrammed and played with the fuel fressure both up & down ( now set @ 40 psi steady). The original problem still exsist. I have no clue where to go from here.
Does anyone know of a good TPI troubleshooting guy in Tucson, Az.? Any new sugestions will be greatly appreciated.
Thanks,
Jerry
 
#26 ·
Typically, fuel pressure is set at 45 PSI, 3 bar the term is called (1 bar = 14.7 psi).

Cold start switch is just what it says, a switch staying 'on' for approx 8 seconds and it provides a current path for the cold start injector. The c/s inj stays on for this approx 8 seconds, it does not pulsate.

Check these events:
1. Base initial timing, disable EST by unplugging the one-wire connector, usually brown-blk wire.
3. TPS setting, measure across the two of the three sensor wires for approx 0.5 vdc, center wire and one of the other two wires with ign sw in 'ign'. Loosen the two screws and rotate the body to accomplish.
2. Base rpm, seat the IAC against the t/b orifice using the ALDL pins A & B shorted together with a paper clip and ign key to ign, no start, no eng running. Then turn key off, unplug IAC connector, set eng idle for 550-700 rpm, no accessories on, just eng running. Stop ign, plug in IAC, clear codes from ECM.

Set these three parameters and start the symptom process over again. Be our luck the eng won't start after waiting.
 
Discussion starter · #27 ·
Everett,
Once again, thanks for your response. I kinda had exactly what you suggest in mind. With the Holidays upon us, I dont know when I'll get back to it. I'll let you know how things work out.
Jerry
 
Discussion starter · #29 ·
I've finally gotten around to playing with it some more and have gotten the time between starts down to about 5 min. I've adjusted the fuel pressure up to aprox 50 psi. Seems to have helped. My timing is set to 0-2* at idle with advance disconnected. With timing advance disconnected, the degrees will "Float" to aprox 0-6* by advancing RPM. Reconnect advance, the timing is aprox 16* at idle and aprox 34-36 * at 3000 RPM. Does the timing sound about right? Still will not restart immediately after shut down. Takes about 5 min between starts "rest" time. I only have maybe 20 miles run time since chip was reprogrammed and reinstalled. Idle when warm is aprox 650-700 and "Hunting". Should I bump idle up to 800 or so. Idle seem to smooth out at around 800 with accelerator pedal. Looking forward to some more of your guy excellent troubleshooting suggestions, Special thanks to Everett.

Thanks all,
Jerry
 
#30 ·
0-2* at idle disconnected? Should be at least 8 if not 12 I'd think. Vacuum advance will put you at 20 or 22* at idle. I think your timing is too retarded.
 
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#32 ·
I think base disconnected timing should be at 6° to 8° BTDC. Check book or engine sticker on hood.

Rpm hunting at low rpm? Might be a broken advance spring or worn bushing. Rpm should be rock solid.
 
#33 ·
I know a TPI motor will surge at idle if you hook the PCV vacuum source hose to the wrong port. There is a TPS calibration procedure you might try. If the calibration (and base idle speed) are off, it can throw the ECM for a loop. http://www.thirdgen.org has an excellent forum for 3rd gen F-body cars. One of their pages has a list of adjustment procedures that tells you how.

The emissions sticker is the place to find base timing as someone else said. If that fails, get a manual, or perhaps thirdgen can help there also. The ECM program has a parameter setting for the base timing and it is at 6*. I PrEsUmE you'd want your initial advance set to the same value. Just be sure to follow the procedure that removes any advance from the ECM. If I recall that involves disconnecting a wire or shorting two wires together...not sure.
 
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Discussion starter · #34 ·
I currently have the PVC vac hose connected at the rear of the upper plenum to the fitting next to the fuel pressure regulator vac fitting. Is this correct?
I was not aware that the distributor had advance springs installed for a computer controlled distributor, if in fact there are springs then this COULD be one of my problems. Hopefully, this coming weekend, I'll get the opportunity to pull the dizzy and check the springs, then I'll advance the timing to 6* and see if this helps.
Thanks,
Jerry
 
#35 ·
Hot 67 said:
I currently have the PVC vac hose connected at the rear of the upper plenum to the fitting next to the fuel pressure regulator vac fitting. Is this correct?
Click to expand...
Vacuum tubing diagram on the hood?
I was not aware that the distributor had advance springs installed for a computer controlled distributor, if in fact there are springs then this COULD be one of my problems. Hopefully, this coming weekend, I'll get the opportunity to pull the dizzy and check the springs, then I'll advance the timing to 6* and see if this helps. Thanks, Jerry
Click to expand...
It may not have springs, I could be mistaken. Yes, getting base timing set/checked would be important.

Also, setting/checking base idle followed by TPS setting will do alot for the ECM control. If TPS set too low or high, ECM will give a fault code for either state. After setting all three items above, dump ECM power to erase codes and let it relearn.
 
Discussion starter · #36 ·
Thanks everyone, with special thanks to Everett for the suggestions. This engine is originally from a 87 IROC Z, but it is currently installed in my 67 Camaro Convertable, so I dont have any emissions data tags/decals or a vaccumn diagram. Timing info and vaccumn hose routing and connections is all from "tribal knowledge". Over time, I've gotten most problems corrected and the car runs absolutely great, with the exception of the restart issue.
I will retime to 6* this weekend and pull the distributor to check for the presence of advance springs or other worn items. Weather has been pretty crappy here for the last couple of weeks (if you call lows of 35+*and 60+*high crappy), so I really havent given the max effort in working this. Hopefully this weekend I can get back own it with full effort.
I'll post results as soon as I can.
Thanks again all,
Jerry
 
#37 ·
Hot 67 said:
This engine is originally from a 87 IROC Z, but it is currently installed in my 67 Camaro Convertable, so I dont have any emissions data tags/decals or a vaccumn diagram. Jerry
Click to expand...
Oh yeah, I forgot.

You didn't transfer the tag? You're welcome, keep us posted.
Maybe a Haynes manual for the 87 Camaro?
 
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Everett#2390
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